Improvement in valve-gears for steam-engines



N. W. WHEELER. VALVE GEAR FOR STEAM ENGINES.

No. 52,475. Patented Feb. 6, 1866.

UNITED STATES PATENT ()FFICE.

NORMAN W. WHEELER, OF BROOKLYN, NEW YORK.

IMPROVEMENT 'IN VALVE-GEARS FOR STEAM- ENGINES.

, Specification forming part of Letters Patent No. 62,475, datedFebruary 6, 1866.

To all whom it may concern Be it known that I, NORMAN W. WHEELER,

of the city of Brooklyn, E. D., county of Kings, and State of. New York,have invented a new and useful Improvement in Valve-Gears forSteam-Engines and I hereby declare that the following is a full andexact description thereof, reference being had to the accompanyingdrawings, making a part of these specifications, and the letters ofreference marked thereon, which letters indicate the same parts in the.differentviews.

Figure 1 represents an elevation, and Fig. 2 an end view, ofa partofthemain shaft and such other parts of a steam-engine as are necessary toillustrate my invention. Figs. 3, 4,

5, and 6 represent-detailed parts; and Fig. 7

is a diagram of a double engine. r

The essence of my invention consists in an eccentric so constructed andapplied to a main shaft that it may be shifted over in a right line fromthe position proper for running the engine one way to the positionproper for running the engine the reverse way, or-to any intermediatepoint, without changing the lead of the valve.

In the drawings, A represents the engineshaft with that part of itslength which carries the eccentric made square, with rabbets B B B Bworked out of the corners; c 0, checkpieces which are fitted to twosides of the shaft, with feathers to fit the rabbets B B B B, and boltedto the grooved clutch-disk g in such a way that by turning thereversingwheel 10 the cheek-pieces c 0 will be moved end-Ion g upon theshaft through the action of the screw 8, nut 'r, levers h h, and, clutchg. The cheek-pieces c 0 have formed upon .them the diagonal feathers EE. The eccentric b is made usually in two parts, fitted to embrace theshaft and cheek-pieces, and with diagonal groovesf f to fit the feathersE E, the parts of the eccentric being bolted together by the ears 1) v,and having sufficient clearance for its proper motion upon the. twosides of the shaft not occupied by the cheek-pieces, and a steady-pin, dd, fitted with its ends resting in the eccentric and sliding freelythrough a hole bored in proper position through the shaft a,preventingthe eccentric from changing its position longitudinally, asshown. The beforedescribed end-long movement of v the checkpieces 0 0will, by reason of the diagonality of the feathersE E and grooves ff,shift thecenter of'the'eccentric I) along theright line D D between thepoints 0 and 0, from which points as centers the dotted outlines w and zof the eccentric are struck.

Now, if the center line D of the eccentric passed through the center ofthe shaft a, then 'D D would coincide with the line E E, and if theeccentric-rod were parallel with the axis of the cylinder, and, further,if a line drawn from the axis of the shaft a throughthe axis of thecrank-pin A were at right angles to the line D D, the proper motionwould be derived from the eccentric b to run theengine either way,according to the position at 0 or o of they center of the eccentric, butin that case the steam-valves could have no lead. Hence the center ofthe eccentric'is placed at such dis--' tauce to one sideof the axis ofthe shaft toward or from the crank-pin, as the case may be, as will givea constant quantity of throw equal to the lap or idle motion and thedesired lead of the valve, which lap and lead motion will be constantfor all positions of the eccentric upon the shaft, the lines D D andbeing parallel to each other.

The action of thisvalve-gear may be otherwise illustrated by comparingit. with the ordinarylink-motion, in which case the centers in g of theeccentric-rods around through considerable angles when the point ofcuttlng off is changed, whereas in the problem before us the lead isconstant, as before described.

1n devices which have heretofore been proposed, including a shifting orsliding eccentric, the path of the center of the eccentric, when shiftedfrom one point to another, was curved, and not a right line, for whatpurpose it is difficult to divine, for that feature would it isradically different and superior, both in a geometrical and mechanicalpoint of view,

to the bell-crank and curved shifting-path device before alluded to.

Having described my invention, I will proceed to state what 1 claim asnovel and desire to secure by Letters Patent, viz

The combination of the eccentric b, cheekpieces 0 0, pin (1 d, andclutch g, or their mechanical equivalents, constructed and coinbinedwith the main shaft, and together, substantiall y as and for the purposedescribed.

' NORMAN W. WHEELER.

Witnesses:

JOHN VAN AMRINGE, S. R. RAND.

